7 ings Discoveries in Vermont Geology. 



the 



Orthocerata to be— like that nearest the Eed Sand-i 



west of Shoreham— of Calciferous age, if not Upper Potsdam. 



The localities affording the Calciferous f< « 

 in Salisbury, Leicester and Brandon lie a little to the west of . 

 the great marble formation; and this marble formation is con- 

 sidered the equivalent of the western " Subcrystalline lime- 

 stone" just above thefucoidal sandstones or Upper Potsdam. 

 The dolomites farther east belong to the Upper Eed Sand-rock 

 series, or else the bottom of the Calciferous, as has been else- 

 where stated. 



The later formations extend less far north than the older 

 because of the inclined axis of the great abraded synclinal: 

 "the Hudson River slates (those of the "central slate-belt") 

 reaching central Wey bridge; the Trenton, about a mile farther; 

 the Rhynchonella beds five or six miles farther north ; and 

 lese disappear, owing to the rising into view of the 

 Red Sand-rock." 



7. The quartzyte of the eastern range, with that also of the 

 local belts in the Eolian limestone area, is regarded as Potsdam 

 (or Primordial) in age, because it contains in many places Sco- 

 lithi (worm-burrows) and Fucoids like those found in the Pots- 

 dam sandstone; because also it adjoins Calciferous limestone 

 beds at the localities just mentioned in North Middlebury and 

 New Haven ; and because it joins the Red Sand-rock in Monk- 

 ton, and one rock has in many places the character of the other, 



not commonly alike in color, and showing differences 

 ble on the ground of the greater metamorphism of the 

 quartzyte. "In Monkton, the Red Sand-rock and the Quartz- 

 yte meet in a succession of short anticlinals, thus cutting off to 

 the north the great trough or synclinal;" and "the Red Sand- 

 rock absolutely overlies the beds of Red Sand-rock in one anti- 

 clinal and the quartzyte in another anticlinal, and both hold 

 Scolxthus linearis. 



8. The quartzyte belt of Rutland Center (just north of Rut- 



in the associated slate, extends north by Sutherland 



Fails nearly to Forestdale, and it runs south of Rutland Center 



■■•ndon and Tinmouth. It lies throughout within the 



mestone area. But it is seen on the map that the area 



Hue of strike of the quartzyte-range north of Pittsford. 



This quartzyte is regarded as Potsdam ; and the limestone which 



lies directly to the west of it i and to the 



West Rutland valley} is supposed to be'possibly the "Ophileta 



beds" or Upper Calciferous, and the "Conglomerate" or Quebec 



